The present invention relates to arrays of horn antennas, and more particularly to a method for designing the horns for non-frequency-dispersive operation over a wide bandwidth.
The bandwidth over which conventional horn antenna feed networks have been operated has been limited to a relatively narrow bandwidth, such that the phase dispersion between horn antennas with differently sized apertures has been kept within an allowable range. A recent innovation, described in the pending patent application entitled "Combined Uplink and Downlink Satellite Antenna Feed Network," filed May 19, 1986, as Ser. No. 864,684 and assigned to a common assignee, is the combination of the previously separate uplink and downlink feed networks in a satellite into one combined network. With such a combined network, the bandwidth over which the horn array must operate is much larger, with the consequence that the phase dispersion between horns of differently sized apertures becomes intolerable. One consequence of the phase dispersion is that the array coverage pattern shifts with frequency.
It would therefore be advantageous to provide a method of designing an array of horn antennas with different aperture sizes in which the horns will phase track over a wide frequency band.